Lubricating oil



April 20, 1937.

LE ROY G. STORY LUBRICATING OIL Filed Aug. l, 1954 10 say 100 F. and 210 F., is desirable.

UNITED STATES PATENT OFFICE LUBRICATING on.

LeRoy G. Story, Glenham, N. Y., asslgnor tovThe Texas Company, New York, N. Y., a corporation of Delaware Application August 1, 1934, Serial No. 737,961

3 Claims.

In the production of high grade lubricating oils,

it is well known that a relatively small change in the viscosity of the oil between temperatures of In other words, it is advantageous for the oil to have a relatively flat viscosity-'temperature curve. which means that the oil has a high viscosity index as dened by Dean and Davis in their article in l5 Chemical and Metallurgical Engineering, vol. 36,

20 from paralnic constituents, thereby producing a resulting raiiinate of increased viscosity index. This procedure involves expensive processing, and results in a reduced yield of nished oil.

The advantage of low pour point of a lubricat- 25 ing oil has long Teen recognized. Paramn base and Mid-Continent lubricating oils have been subjected to dewaxing in order to reduce'the pour point thereof. However, substantially complete removal of wax from such oils results in a lowering in viscosity index.

The present invention relates to the increase in viscosity index of naphthene base or parafiin base lubricating oils, by blending therewith a proportion of a material which is active to increase the viscosity index without objectionably affecting other desirable properties thereof. The invention also relates to the preparation of a synthetic lubricating oil of high viscosity index which is suitable for the above purpose, and which is the oily condensation product obtained by condensing in the presence of a metallic halide condensation catalyst the chlorinated product of a cracked waxy hydrocarbon material.

. U. S. Patent No. 1,955,260, dated April 17. 1934, discloses the production of a synthetic lubricating oil by cracking a waxy hydrocarbon material, and then condensing the cracked product with a catalyst such as anhydrous aluminum chloride. In co-pending application, Serial No. 732,091, filed June 23, 1934, a synthetic lubricating oil ls produced by chlorinating a waxy hydrocarbon, and then condensing the chlorinated product in the presence of a condensation catalyst such as anhydrous aluminum chloride. Each of these meth- 55 ods is subject to practical limitations in the quantity of yield and quality of product produced, because the cracking or the chlorinationstep can only be carried to an intermediate reaction stage in practical operation. Consequently, a comparatively lower yield of product which is inferior to that of the present invention is obtained. The present invention combines both the pre-cracking and pre-chlorination steps prior to condensation, with the result that the eiect is cumulative, and higher yields of a product of superior character are obtained.

In accordance with the present invention a waxy hydrocarbon, such. as parafiin wax, petrolatum, wax tailings, slack wax, as well as heavy oils containing Wax and consisting essentially of straight chain hydrocarbons, are utilized as starting materials. For purposes of description, each of the above materials is hereinafter designated in the description and claims as a waxy hydro-- carbon material. The high boiling straight chain hydrocarbon material is iirst subjected to mild cracking to produce a large yield of partially cracked high boiling hydrocarbons and a small amount of tar and low boiling products. This cracking operation may be carried out under vapor phase conditions, preferably under low pressures such as atmospheric to about 100 lbs. per square inch or below, and at temperatures between about '750 and ll00 F. A heavy distillate oil is obtained from the cracked products by fractionation.

The cracked product, such as the distillate oil, is then subjected to chlorination, as by passing chlorine through the material at slightly elevated temperatures. The chlorination product is then condensed in the presence of a metallic halide condensation catalyst, such as anhydrous aluminum chloride. vA heavy synthetic lubricating oil of high viscosity index, generally well in excess of 100, is then separated from the condensation product. This oil may be used alone as a lubricating oil of superior or special character. Preferably, the synthetic oil is blended with a petroleum lubricating oil in order to improve the character of the latter. 'I'he proportions in which the several oils maybe blended vary widely, but proportions of about l0-50% of the synthetic oil to 90-50% of a petroleum lubricating oil give very satisfactory results.

Referring to the accompanying drawing, a ow sheet of the process of the present invention is illustrated. This is hereinafter described in connection with a specific example falling within the scope of the invention. A paraffin wax is passed from a source of supply i0 toa cracking still Il Where it is primarily vaporized and the vapors heated at atmospheric pressure to a temperature of about 800-900 F. to eiect cracking. The

.cracked vapors are fractionated in a fractionating tower l2, where lighter vapors are removed overhead through suitable condensers to receiving tank i3, and a heavier distillate oil containing a substantial proportion of unsaturated hydrocarbons is removed as a side stream to receiving tank ll. The residue, which is a tarry material, is passed to tank l5.

The distillate oil is supplied from tank I4 to a chlorinating vessel I1, to which chlorine gas is supplied from drum I8. The Aoil in the chlorinator is preferably maintained at about -25 F., and is agitated during the time that a stream of chlorine gas is passed therethrough. For example, a proportion of about 1012% chlorine on the weight of the oil may be employed. This serves to form chlorine substitution products of the uncracked and mildly cracked paraiiins and addition products of a portion of the unsaturated hydrocarbons. p

The chlorinated material is then passed to a. condensation vat 20, to which anhydrous aluminum chloride is supplied from bin 2l. The oil is preferably maintained at a temperature slightly above the melting point which may range from about 50-125 F. and is agitated during the condensation treatment, which may be continued for about 18-24 hours. A proportion of about 3-5% of anhydrous aluminum chloride may be employed. Ihe condensation product isA then passed to a settling tank 22 where the aluminous sludge is separated and passed to receiving tank 23 from where it may be returned for reuse in the condensation reaction. The resulting oil is passed to storage 24, and is preferably contact ltered in the presence of acid treated clay in the treating tank 25. The oil of improved color and free from suspended impurities is then distilled in a vacuum still 26 to remove lighter products which are collected in receiving tank 21, and to obtain a heavy synthetic oil of high viscosity index which is passed to storage tank 28. Residuum from the vacuum still is discharged to receiver 29. An oil of lubricating character and having a viscosity index of about -150 may thus be obtained.

Where this oil is to be blended with a petroleum lubricating oil, this is accomplished by introducing predetermined proportions of the synthetic oil from storage 28, and a petroleum lubricating oil from storage 30, into a blending tank 3l, from which the blended oils are discharged to an oil storage 32 for distribution or further treatment.

While anhydrous aluminum chloride constitutes a Very satisfactory condensation catalyst for the production of the above synthetic lubricating oil, it is to be understood that other metallic halide condensation catalysts of the Friedel-Craft type can be employed, such for example, as the chlorides or other halides of cobalt, manganese, iron, boron, nickel, zinc, antimony, cadmium, tin and the like.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims. y

I claim:

l. The method of producing a synthetic lubricating oil which comprises mildly cracking a waxy hydrocarbon material containing primarily saturated hydrocarbons at temperatures Within the range of '1501100 F. and at pressures below 100 pounds per square inch to produce a product containing a substantial proportion of unsaturated hydrocarbons, separating a heavy distillate oil containing a substantial proportion of unsaturated hydrocarbons from the cracked product, chlorinating the heavy distillate oil by passing chlorine therethrough at slightly elevated temperatures to produce substitution compounds of saturated hydrocarbons remaining in the distillate oil separated from the cracked product, condensing the chlorinated oil in the presence of a metallic lalide condensation catalyst at temperatures within the range of 50-l25 F. for about 18-24 hours, and separating a synthetic lubricating oil of high viscosity index from the condensation product.

2. The method of producing a synthetic lubricating oil which comprises mildly cracking a waxy hydrocarbon material containing primarily saturated hydrocarbons to produce a product containing a substantial proportion of unsaturated hydrocarbons, chlorinating the cracked product to produce substitution compounds of saturated hydrocarbons remaining in the cracked product, and then condensing the chlorinated cracked product in the presence of a metallic halide condensation catalyst to obtain a lubrieating oil.

3. The method of producing a synthetic lubricating oil which comprises mildly cracking paraiiin Wax to produce a product containing a substantial proportion of unsaturated hydrocarbons, chlorinating the cracked product to produce substitution compounds of saturated hydrocarbons remaining in the cracked product, and then condensing the chlorinated cracked product in thef presence of aluminum chloride to obtain a lubricating oil.

LE ROY G. STORY. 

